Headlamp comprising energy absorption means

ABSTRACT

The invention relates to a headlamp for a motor vehicle, comprising a housing enclosing a light source, fixed on a chassis, together with means for connecting the housing to the chassis, these means being deformable in a plastic way and capable of absorbing at least part of the energy of an impact on the headlamp.

The present application is a continuation of U.S. application Ser. No.10/665,764, filed Sep. 18, 2003, the contents of which is herebyincorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a headlamp for a motor vehicle,comprising a housing fixed on a chassis and enclosing a light source forilluminating the vehicle.

BACKGROUND OF THE INVENTION

As vehicle manufacturers have known for a considerable time, headlampshave an important function in the passive safety of vehicles,particularly in respect of pedestrians with whom collisions may occur.

Such collisions can result in major bodily injury, even at low speeds(less than 40 km/h). Consequently, headlamps are commonly provided withenergy absorption means in order to reduce the impact suffered by apedestrian and thus decrease the risks of serious bodily injury.

One particular example of a headlamp provided with energy absorptionmeans is known from the European Patent Application published under thenumber EP-1,059,200.

Although known headlamps of this type have enabled considerable progressto be made in respect of passive safety, they have a certain number ofdisadvantages.

In particular, the addition of energy absorption means frequentlyrequires significant structural modifications of the headlamp, with theaddition of numerous parts which make the headlamp more bulky, increaseits weight and add to its cost.

The object of the invention is, in particular, to mitigate the aforesaiddisadvantages by proposing a headlamp which, while providing optimalpassive safety, particularly in respect of pedestrians, has relativelysmall overall dimensions and comprises a limited number of parts.

SUMMARY OF THE INVENTION

For this purpose, the invention proposes a motor vehicle headlamp of theaforesaid type, which additionally comprises plastically deformablemeans for connecting the housing to the chassis, these means beingcapable of absorbing, preferably without breaking, at least part of theenergy of an impact on the headlamp.

The invention uses the term “headlamp” in the broadest sense, includingany lighting and/or indicating device for a vehicle.

The headlamp thus has relatively limited overall dimensions, while stillhaving good energy absorption capacity. It is also simple to manufactureand its cost has been found to be relatively low.

There are various possible embodiments for the application of theinvention.

In a first embodiment, the deformable means can operate in tension.

Thus the deformable means can comprise a lug for fixing the housing tothe chassis, this lug being capable of stretching under the effect of animpact on the headlamp.

The lug comprises, for example, a perforated body extended at one end bya front part fixed to the chassis, and at the other end by a rear partfixed to the housing, the body being capable of stretching under theeffect of traction exerted on said parts. The lug can comprise aperforated or unperforated body, having at least one area of contractedcross section locally. The perforations in the body are of variousshapes, for example rectangular, square, any polygonal or hexagonalshape, or diamond-shaped, or possibly circular or oval.

In a variant, the fixing lug has a corrugated central portion extendedat one end by a front part fixed to the chassis, and at the other end bya rear part fixed to the housing, the central portion being capable ofstretching under the effect of traction exerted on said parts.

In a second embodiment, the deformable means can operate by bending.

Thus the deformable means can comprise a lug for fixing the housing tothe chassis, the lug having a U-shaped profile and comprising twoapproximately parallel branches, one fixed to the housing and one to thechassis, linked by a curved portion, the lug being deformable by thedisplacement of the curved portion under the effect of an impact on theheadlamp.

In a third embodiment, the deformable means can operate by compression.

Thus the deformable means can comprise a lug for fixing the housing tothe chassis, the lug being compressible under the effect of an impact onthe headlamp.

This kind of fixing lug has, for example, a corrugated central portionextended at end by a front part fixed to the housing, and at the otherend by a rear part fixed to the chassis, the corrugations being capableof being compacted under the effect of an impact on the headlamp.

Instead of this kind of fixing lug, the deformable means can comprise aspacer interposed between the housing and the chassis.

A spacer of this kind can be made, for example, from a compressiblematerial, such as aluminum foam.

In a variant, the spacer comprises a cylindrical barrel, pressed againstthe chassis at one end and extended at the opposite end by a curved headby means of which the spacer is pressed against the housing.

In yet another variant, the spacer is a functional component of thevehicle, such as an air filter or a windscreen washer reservoir.

The invention will be made clearer by the following description,provided purely by way of example and with reference to the attacheddrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional elevation of a motor vehicle headlamp providedwith deformable connecting means, comprising a fixing lug designed tooperate by traction and having a perforated body;

FIG. 2 is a view from above of a fixing lug designed for a headlamp suchas that of FIG. 1, shown in isolation, in the absence of any stress;

FIG. 3 is a view from above of the lug of FIG. 2, after it has beensubject to a tensile stress;

FIG. 4 is a view similar to that of FIG. 1, in which the headlamp isprovided with deformable connecting means comprising a corrugated fixinglug designed to operate by traction;

FIG. 5 is a view similar to that of FIG. 1, in which the headlamp isprovided with deformable connecting means comprising a curved fixing lugdesigned to operate by bending;

FIG. 6 is a view similar to that of FIG. 1, in which the headlamp isprovided with deformable connecting means comprising a corrugated fixinglug designed to operate by compression;

FIG. 7 is a view similar to that of FIG. 1, in which the headlamp isprovided with deformable connecting means comprising a spacer made froma compressible material;

FIG. 8 is a detail view showing part of a headlamp mounted on a fixedchassis with the aid of connecting means comprising a deformable tubularspacer;

FIG. 9 is a perspective view showing a headlamp mounted on a fixedchassis by means of a functional component of the vehicle;

FIGS. 10 and 11 are variants of FIGS. 2 and 3 and are views of lugswhich can be deformed by traction.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a headlamp 1 of a motor vehicle, comprising a housing 2enclosing a certain number of internal components (not shown), includinga light source and a reflector on which is mounted the source whoselight is reflected and diffused by the reflector.

For convenience, the general direction of illumination of the headlamp 1will be called the longitudinal direction. In practice, this directionis identical to the direction of movement of the vehicle.

The headlamp 1 also comprises a lens 3 mounted on the housing 2, whichit covers in a similar way to a lid, to protect the internal componentswhile transmitting in the forward direction the light emitted by thelight source.

The housing 2 is fixed on a chassis 4 consisting of the chassis of thevehicle, with the aid of plastically deformable connecting means 5,which, when undergoing deformation, can absorb at least part of theenergy of an impact on the headlamp 1 without breaking.

In case of a collision with an obstacle, the latter strikes the lens 3,which moves backwards from its normal operating position in which it isflush with the adjacent bodywork elements 6 and 7, and pushes thehousing 2 backwards.

The housing 2 then exerts on the connecting means 5 a stress which,depending on the configuration of these means, may be tensile, bendingor compressive.

In a first embodiment, described here with reference to FIGS. 1 to 4,the connecting means 5 are designed to operate by traction.

In a first variant, shown in FIGS. 1 to 3, the connecting means 5comprise a lug 8 for fixing the housing 2 to the chassis 4, this lugbeing approximately flat and capable of stretching under the effect ofan impact on the headlamp 1. This lug 8 is made from a material havinglow elastic deformability, such as steel or a hard thermoplastic.

As shown in FIG. 2, the lug 8 has a perforated central body 9, piercedwith a set of holes 10 of rectangular section. The holes 10 help thebody 9 to deform. The body 9 is extended at one end by a front part 11fixed to the chassis 4, and at the other end by a rear part 12 fixed tothe housing 2.

For fixing the front part 11 and the rear part 12, these are piercedwith holes 13 for the passage of fixing screws, which can engage,respectively, with the chassis 4 and the housing 2. The housing can alsobe provided with a projecting support strip 14 for fixing the rear part12, as shown in FIG. 1.

When fixed at its two ends, the lug 8 extends longitudinally between thehousing 2 and the chassis 4. When the housing 2 is displacedlongitudinally rearwards by the pressure of the obstacle, it tends todraw with it the rear part 12 of the lug 8 which, being fixed to thechassis 4 by its front part 11, stretches under the effect of thetensile stress thus exerted on the parts 11 and 12, by plasticdeformation.

This deformation takes the form of an elongation and a thinning of thebody 9, promoted by the presence of the perforations or holes 10, whilethe parts 11 and 12 largely retain their initial shape, as shown in FIG.3. By deforming without breaking, the lug 8, which acts in the same wayas a tensile test piece, absorbs at least part of the energy of theimpact.

In the illustrated example, the headlamp 1 has two fixing lugs 8, onebeing fixed on an upper wall 15 of the housing 2 and the other on alower wall 16. Clearly, it is possible to provide larger number of theselugs 8, in order to increase the energy absorption capacity of theheadlamp 1.

FIGS. 10 and 11 are variants, showing lugs 8′ with bodies 9′ havingrectangular perforations 10′ (FIG. 10) or hexagonal perforations (FIG.11) before (a) and after (b) deformation due to traction. FIG. 10 showsa lug having a contracted cross section in the “solid” area delimitingthe two perforations. In FIG. 11, the shape of the perforations is suchthat there is a de facto contraction of the lug in the area of the bodydelimiting the two perforations. In both cases, as a result of tractionat the time of impact, the perforations 10′ are stretched, the lug 8′then being elongated overall by at least 10% of its initial totallength, by approximately 20% for example. The elongation may also begreater, depending on the type of material and the shape of the lug.

In a second variant shown in FIG. 4, the connecting means 5 comprise alug 17 for fixing the housing to the chassis which has a corrugatedcentral portion 18 extended at one end by a front part 19 fixed to thechassis 4, and at the other end by a rear part 20 fixed to the housing2.

The lug 17 is made, for example, by cutting and bending from a sheet ofmetal such as a steel sheet, or by thermoforming a hard thermoplasticmaterial.

As described previously, the parts 19 and 20 can be pierced with holes21 for the passage of fixing screws, the housing 2 being provided with aprojecting support 14 for fixing the rear part 20.

If the headlamp 1 collides with an obstacle, the housing 2 is pushedlongitudinally backwards and pulls on the lug 17 whose corrugatedportion 18 is stretched, undergoing plastic deformation withoutbreaking, under the effect of the tractive force exerted in this way onits parts 19 and 20.

The headlamp 1 comprises two fixing lugs 17, as in the first variantdescribed above, but a larger number could be provided, depending on thelevel of energy which the headlamp 1 is intended to absorb.

In a second embodiment shown in FIG. 5, the connecting means 5 canoperate by bending, and for this purpose comprise a curved lug 22 forfixing the housing 2 to the chassis 4, the lug being positioned betweenthe latter components.

This lug 22, which has a U-shaped profile, comprises two approximatelyparallel and longitudinally extending branches 23 and 24, namely aninner branch 23, fixed to the housing 2, and an outer branch 24, fixedto the chassis 2, the branches 23 and 24 being linked by a curvedportion 25 whose concavity faces forwards.

As shown in FIG. 5, the outer branch 24 is provided with a part bent ata right angle 26, pierced with a hole 27 for the passage of a screwwhich can engage with the chassis 4 to fix the branch 24 to the latter.

The inner branch 23 is also pierced with a hole 27 for the passage of ascrew which can engage with a wall of the housing.

Under the effect of an impact on the headlamp 1, the housing 2 is pushedlongitudinally backwards by the lens 3 which has struck the obstacle. Inits movement, the housing 2 pulls along the inner branch 23 of the lug22, while the outer branch 24 remains fixed to the chassis 4. The lug 22is then deformed in a plastic way, without breaking, by rollingbackwards, as shown in broken lines in FIG. 5 (in fact, an area ofconstant deformation is maintained in this movement).

In this case, two lugs 22 are provided, one fixed on an upper wall 15and one on a lower wall 16 of the housing 2. However, as in the previouscase, it is possible to have a larger number of lugs in order toincrease the energy absorption capacity of the headlamp 1.

In a third embodiment, shown in FIGS. 6 to 9, the connecting means 5 canoperate by compression.

Thus, in a first variant, shown in FIG. 6, the connecting means 5comprise a compressible lug 17′ for fixing the housing 2 to the chassis4, comprising a corrugated central portion 18′ extended at one end by afront part 19′ fixed to the housing 2 and at the other end by a rearpart 20′ fixed to the chassis 4, the parts 19′ and 20′ being piercedwith holes 21 for the passage of fixing screws.

As shown in FIG. 6, the housing 2 is also provided with a projecting lug14 for fixing the front part 19′.

As will be understood, this compressible lug 17′ has a similar shape tothat of the stretchable lug 17 described above. Like the latter, it canbe made by cutting and bending a sheet of metal such as a sheet ofsteel, or by thermoforming a hard thermoplastic material.

If the headlamp 1 collides with an obstacle, the housing 2 is pushedlongitudinally backwards and tends to push back the lug 17′, whosecorrugated portion 18′ is compressed, undergoing plastic deformationwithout breaking, under the effect of the compressive force exerted inthis way on its parts 19′ and 20′.

In a second variant, shown in FIG. 7, the connecting means 5 comprise aspacer 29 interposed between the housing 2 and the chassis 4, in theform of a cylindrical or prismatic block made from a compressiblematerial, preferably an aluminum foam, which has good energy absorptioncapacity.

A plurality of these spacers 29 can be placed between the housing 2 andthe chassis 4, to increase the absorption capacity of the headlamp 1. Inthe present case, two spacers 29 are provided, each being interposedbetween the chassis 4 and a fixing lug 14 projecting from the housing 2.

As shown in FIG. 7, each spacer 29 is pierced with a hole 30 for thepassage of a screw for fixing the housing 2 to the chassis 4.

In the course of the impact, the housing 2 moves longitudinallybackwards, causing the compression of the spacers 29, which in thecourse of their plastic deformation absorb at least part of the energyof the impact.

In a third variant, shown in FIG. 8, the connecting means 5 comprise aspacer 31, which is interposed between a wall of the housing formed, forexample, by a projecting lug 14, and which is provided with acylindrical barrel 32, terminating rearwards in an end 33 which bears onthe chassis 4, and extending in the opposite direction, in other wordsin the forward direction, in the form of a curved head 34.

As shown in FIG. 8, the barrel 32 is hollow, a screw 35 passing throughboth the wall 14 of the housing and the barrel 32 to engage with thechassis 4 and thus fix the housing 2 whose wall 14 bears on a toroidalpart 36 which connects the head 34 to the barrel 32.

Under the effect of an impact on the headlamp 1, the housing 2 moveslongitudinally backwards and crushes the head 34, the wall 14 pushingback the toroidal connecting part 36, as shown in broken lines in FIG.8. In other words, the spacer 31 contracts in the direction of its rearend 33.

When compressed in this way, the spacer 31 is deformed in a plastic way,absorbing at least part of the energy of the impact without breaking.

In a fourth variant, shown in FIG. 9, the means 5 for connecting thehousing 2 to the chassis 4 comprise a functional component 37 of thevehicle, on which component 37 the housing 2 is mounted.

As shown in FIG. 9, the housing is fixed directly to the component 37 bymeans of projecting lugs 14, the component 37 being in turn fixed to thechassis 4 of the vehicle by lugs 38.

This component 37 is, for example, an air filter or a windscreen washerreservoir. Such a component 37 has the advantage of being constructedwith a good capacity for absorbing the energy of an impact withoutbreaking.

Thus, regardless of the embodiment chosen, the connecting means 5 have agood capacity for absorbing the energy of an impact on the headlamp 1,thus enhancing the safety of pedestrians for whom the risks of seriousbodily injury are thus reduced, the arrangement of the connecting means5 also enabling the overall dimensions of the headlamp 1 to be limited.

Clearly, the connecting means 5 described above can easily be added to aconventional fixed headlamp without the need for a comprehensiveredesign of the headlamp.

1. A headlamp for a motor vehicle, comprising: a housing enclosing alight source, fixed on a chassis, which comprises means for connectingthe housing to the chassis, these means being deformable by bending andcapable of absorbing at least part of the energy of an impact on theheadlamp, wherein the connecting means comprise a lug for fixing thehousing to the chassis, this lug being compressible under the effect ofan impact on the headlamp.
 2. The headlamp as claimed in claim 1,wherein the connecting means comprise a spacer interposed between thehousing and the chassis.
 3. A headlamp for a motor vehicle, comprising ahousing enclosing a light source, fixed on a chassis, which comprisesmeans for connecting the housing to the chassis, these means beingdeformable by bending and capable of absorbing at least part of theenergy of an impact on the headlamp, wherein the connecting meanscomprise a spacer interposed between the housing and the chassis.
 4. Theheadlamp as claimed in claim 3, wherein the spacer is made from acompressible material.
 5. The headlamp as claimed in claim 3, whereinthe spacer is made from a foam.
 6. The headlamp as claimed in claim 3,wherein the spacer comprises a cylindrical barrel having a first endpressed against the chassis and its opposite end extended in the form ofa curved head by means of which the spacer presses against the housing.7. The headlamp as claimed in claim 3, wherein the spacer is afunctional component of the vehicle.
 8. The headlamp as claimed in claim3, wherein the spacer is an air filter.
 9. The headlamp as claimed inclaim 3, wherein the spacer is a windscreen washer reservoir.
 10. Aheadlamp for a motor vehicle, comprising a housing enclosing a lightsource, fixed on a chassis, at least one lug for fixing the housing tothe chassis, said at least one lug comprises a perforated body having across section and at least one contracted cross section thereof andbeing capable of stretching by traction under the effect of an impact onthe headlamp for absorbing at least part of the energy of an impact onthe headlamp.
 11. A support for fixing a headlamp housing of a motorvehicle to the chassis of the motor vehicle comprising: at least one lughaving a body with a cross section, said body including at least onecontracted cross section, said body being capable of stretching bytraction under the effect of an impact on the headlamp for absorbing atleast part of the energy of an impact on the headlamp.